Sound in a coronary care unit in the form of noise and human communication serves as a potential stressor to patients. The stress can result in increased oxygen requirements, catecholamine release, and cardiac irregularities. The purpose of this study is to determine the cardiovascular effects of noise and communication in coronary care patients with varying levels of trait anxiety. The hypotheses address the relationship of cardiovascular variables (heart rate, blood pressure and arrhythmias) to anxiety level under four different sound conditions (quiet ambient sound, meaningless sound, human communication sounds, and environmental sound); in three different role relationships (nurse, physician and family); and in response to different types of communication (confirmation and disconfirmation), and different topics of conversation. A repeated measures design will be used with twenty patients post myocardial infarction or angina in a large midwestern teaching hospital. Cardiovascular data and sound in the patients' rooms will be recorded at three different time periods that will include noisy and quiet times as well as during times when the patient is communicating with nurses, physicians, and family. Meaningless noise will be intermittently introduced after a quiet half hour. Physiological data will be obtained using the patient's monitor for electrocardiogram and heart rate and a Dinamap for blood pressure. Sound pressure level in decibel will be measured with a sound level meter and a microphone placed above the patient's head. Communication will be recorded and analyzed using a Confirmation Rating Instrument. Communication will be categorized by content to topics and role of the other person in communication with the patient. Anxiety scores will be correlated with physiological measures under four sound conditions and may be used as a co-variate. Repeated measures ANOVA will be used to compare physiological and communication variables at different sound levels and in different role relationships. Knowledge about noise and communication in intensive care settings is needed to understand patients' responses to their environment. This knowledge will assist health care providers to promote maximal adaptation and optimal recovery in critically ill patients.